Land-clearing fires foul Malaysia's air

KUALA LUMPUR, Malaysia (CNN) -- The thick, smoky haze covering Malaysia has gone from bad to worse, forcing the government to declare a state of emergency Friday.

So hazardous is the air quality that Malaysian Prime Minister Mahatir Mohamad wore a surgical mask in public -- and urged his countrymen to do the same.

The haze spreading across Malaysia and other parts of Southeast Asia is coming from neighboring Indonesia. There, thousands of fires have been deliberately set by loggers and farmers, using a land-clearing technique called "slash and burn."

"I think it's really an indication of the fact that Indonesia, and probably Malaysia as well, do not have control over their forest situations," said Christopher Flavin of the Worldwatch Institute. "They are going to be suffering economic as well as health consequences."